Immersion Heater Thermostat Knocking

[sparkypants]

Evening all.

Just had a callout to an immersion heater making wierd knocking sound within 30 seconds or so of being switched on. Seems to be the thermostat in the dry pocket and if I hold the thermostat then the knocking stops.

Polarity, voltage etc correct. Top 22" immersion heater...

Need help!

 

[telectrix]

if a plumber has been there, that's your answer. element may have been bent to get it in easily and is touching the side of the tank.

 

[sparkypants]

Cheers guys - I'll try PTFE tape as Maplins is miles away and I haven't got the heart to bend his themostat

 

[dingledong]

do you think the plumber dropped his wallet into the cylinder so not much water could get into it